Surgical staplers have become a very typical form of wound closure. These surgical staplers can provide various functions such as closing internal wounds, as well as suturing skin. In addition, staplers are useful in endoscopic purposes. Many of these surgical staplers have reloadable cartridges. These cartridges allow for the rapid reloading of the stapler during an operation. That is, the stapler can be used, the spent cartridge removed, and the surgical stapler reloaded with another cartridge to once again be ready for use.
A problem associated with the reloadable cartridges contained in surgical staplers commonly in use is the potential refiring of staplers containing spent cartridges. In other words, during the course of surgery it may be possible for the surgeon to use the stapler and then inadvertently not reload the stapler with an unused cartridge. The stapler is then inserted into the wound for use, and then fired. Of course, because the stapler cartridge is already spent, there will be no staples forthcoming from the stapler to fire another round of staples into tissue. This results in a delay while reloading the stapler cartridge. Also, if there is a knife mechanism associated with the stapler, the potential for wounding the patient exists.
In Fox, U.S. Pat. No. 4,892,244 there is described a stapler lockout mechanism which causes a barrier to be placed within the path of the firing mechanism. The Fox device prevents the refiring of the stapler once the stapler cartridge has been fired.
Schulze et al., U.S. Pat. No. 5,129,570 similarly describes a cartridge lockout mechanism device. It provides a cartridge which has a slot disposed within adjacent rows of staples, and wherein the slot extends substantially the entire length of the rows of staples. The stapler includes firing means for the staples and cutting means moveable in the slot. The stapler also includes a lockout mechanism for preventing movement of the cutting means in the slot. The lockout mechanism comprises a leaf spring disposed in the stapler and engages the bottom or lower surface of the knife mechanism forming the cutting means, to place the cutting means in a first position. In this first position, the cutting means is out of alignment with the slot contained in the stapler cartridge. In addition, there are means disposed on the cartridge for engaging the upper or top surface of the cutting means. The means for engaging the top surface of the cutting means depresses the leaf spring and moves the cutting means from its first position to a second position. In the second position, the cutting means is in alignment with the slot, so that the cutting means may move within the slot. After firing of the stapler, the means for engaging the top surface of the cutting means is moved, so that it no longer engages the cutting means. In this way, the cutting means is forced to remain in the first position, and therefore is out of alignment with the slot of the staple cartridge, so that firing the stapler is no longer possible.
It will be appreciated that various other lockout mechanisms have been disclosed in the art. However, all of these lockout mechanisms require movement by one or more moving members in the surgical stapler. None of the lockout mechanisms describe a stapler which contains a device inherently capable of locking out the cartridge without the lockout mechanism itself moving. It may be desirable to provide such a non-moving cartridge lockout mechanism.